RT Journal Article SR Electronic A1 Van de Vijver, Bart A1 Kopalová, Kateřina A1 Zidarova, Ralitsa T1 Revision of the Psammothidium germainii complex (Bacillariophyta) in the Maritime Antarctic Region JF Fottea YR 2016 VO 16 IS 2 SP 145 OP 156 DO 10.5507/fot.2016.008 UL https://fottea.czechphycology.cz/artkey/fot-201602-0001.php AB Psammothidium germainii is a widespread freshwater monoraphid diatom species in the Antarctic Region. Detailed analysis of the populations in the different parts of the Antarctic Region revealed the presence of several species that were lumped under the name 'P. germainii'. The type material of both Achnanthes germainii and Achnanthes ninckei has been investigated to allow a better morphological delimitation of both taxa and to better characterize the new taxa. Two new taxa are proposed: Psammothidium rostrogermainii sp. nov., typical for its rostrate apices and its rather distantly spaced stria pattern, and Psammothidium germainioides sp. nov., formerly identified in Antarctica as Achnanthes ninckei. Both new taxa are illustrated using light and scanning electron micrographs and are compared with similar taxa worldwide. Additionally, two populations of Psammothidium germainii lacking a raphe on the raphevalve are illustrated and discussed.